An electric pump provided with an electric motor is used to pneumatically send oil to, for example, a drive motor in an electric automobile or a hybrid motor vehicle, or to a gearbox or the like connected to the drive motor.
Patent Document 1 discloses an electric pump in which a pump rotor of a pump unit is fixed to a first end of a rotation shaft rotatably supported in a housing and a rotor of an electric motor is fixed to a second end of the rotation shaft, wherein a driver unit that operates the electric motor is contained in an accommodation space recessed in an end surface of the housing and is then covered with a cover.
The driver unit is made by attaching many parts to a substrate. Of the many parts attached to the substrate, large parts of the driver unit such as a capacitor is arranged on the substrate so as to be located in the recess of the accommodation space.
In the housing, there is erected a connector unit for supplying electric power to the driver unit. The connector unit is made of: a connection terminal that extends through the housing, a first end of the connection terminal being connected to the driver unit inside the housing and a second end thereof being exposed to an outside via a through-hole of the housing; and a connector main body that surrounds the second end of the connection terminal.
To the connector unit, a harness led out from an external power source is connected. As a result, the external power source outside the housing and the driver unit inside the housing is electrically connected via the connection terminal of the connector unit, causing the electric power to be supplied from the external power source to the driver unit.
Patent Document 2 discloses an electric pump including: a pump unit; a motor unit that drives the pump unit; a conductive motor housing that contains at least the motor unit; and a driver unit (corresponding to the “control device” in the claims) that controls the motor unit.
From an opening formed in an end face of the motor housing, a terminal unit (corresponding to the “motor electricity-supplying terminal” in the claims) for electrically connecting between a coil of the motor unit and a substrate in the driver unit protrudes toward the driver unit. Into a mount of the driver unit, a terminal bent into a U-shape is buried by insertion molding. Of the U-shaped terminal, a first end is used as a terminal to be connected to the substrate while a second end is used as a connection section with a protrusion that is brought into contact with the terminal unit when assembled. In the mount of the driver unit, a through-hole into which the terminal unit is to be inserted is formed. When the driver ASSY is fixed to the motor housing, the terminal unit is inserted through the through-hole into contact with the protrusion of the U-shaped terminal. This allows an electric current to pass from the substrate to the coil.
Thus, according to Patent Document 2, only inserting the terminal unit into the through-hole allows the terminal unit of the motor unit and the U-shaped terminal of the driver unit to be electrically connected. Therefore, this is expected to simplify the manufacturing steps.
Incidentally, there are cases where an electric pump is installed and used in an environment exposable to water such as in an engine room or in the vicinity of a gearbox of a motor vehicle. Therefore, an electric motor and an electric pump may require waterproofness.
Because an electric pump is mounted, for example, in an engine room or in the vicinity of a gearbox of a motor vehicle, there are cases where the layout is restricted. Therefore, an electric motor and an electric pump are required to be made smaller.
For example, as is described in Patent Document 1, there are cases where a brushless motor is used as this electric motor. A control device for operating the brushless motor is roughly made of: a driver unit (corresponding to the “motor drive unit” in the claims); and a control unit (corresponding to the “motor control unit” in the claims). Therefore, for containing the control device in an accommodation space of a housing with a limited size, it is necessary to take the layoutability of the driver unit and the control unit into consideration.
In the structure of Patent Document 2, it is necessary to mechanically join the terminal unit of the motor unit and the U-shaped terminal of the driver unit together by, for example, welding or the like in order to further improve the reliability of the electric connection. A variety of welding methods are available. However, generally speaking, in order to connect terminals that overlap each other, resistance welding such as projection welding or spot welding is preferable. Resistance welding is performed in this manner. A main electrode bar and a sub electrode bar are brought into contact respectively with the two terminals in the direction in which the two terminals overlap each other. While pressure is being applied to the bars, electric power is passed between the main electrode bar and the sub electrode bar via the two terminals.